Vega is a perfect fighting game villain because he is as frustrating to challenge as he is satisfying to defeat, and I do think he’s a lot more compelling as an antagonistic force towards the likes of Chun-Li or Ken or Cammy than he is as a character unto himself. There’s some reasons why the fights with Vega, in the animated movie or in II V or in the Udon comic, tend to be seen as the high points of Street Fighter adaptations.

Largely because as an antagonist to them, he is uniquely vicious and horrifying and murderous to an extent no other SF character is, he escalates any situation into a fight for survival just by walking into the room, while still occasionally allowing strange moments of poignancy due to his skewed honor and priorities, at least when Cammy is involved, and also being by design extremely satisfying to beat and watch get beaten. He is not just a punchable goon and smug champion like Balrog, he is also a creep and a serial killer, and an extremely privileged one at that, which makes beating and humiliating him a moral imperative on top of everything else. That, along with the fact that he’s blatantly cheating with that claw and protecting his face with a mask, not just because he is desperate to preserve his good looks but because he doesn’t even want to touch you as he kills you, is part of what makes him arguably the most punchable character in the series, or at least, the best designed for that purpose. That is, of course, if the player can catch him, which his whole playstyle is designed to avoid. Vega can and will fly circles around you as he wears you down, and like any nobleman, he will attack you from distances and positions you can’t strike him back from, and it will wear on your patience, making it all the more satisfying if you do catch and smash him, which is still a big If.

And as a character onto himself, he’s someone who’s pretty much got his life figured out and as a result only truly wants what he can’t have. He is a nobleman who’s been gifted with wealth, power, skill, charm, intellect, beauty, and everything he could possibly desire, including the ability to kill people with impunity on a regular basis. He is a guy who lives his perfect life, but who still takes it upon himself to put on a mask and go out at night and viciously murder people he deems ugly, not just because their existence makes his world less perfect for it, but because championing the superiority of beauty by subjugating the ugly is the only form of meaning Vega can find in life. He lives reveling in his own futility and only comes alive when faced with a challenge he can take pleasure in vanquishing, which is right around the time when he either loses and vanishes to preserve his pride, or gets his face smashed or even just touched and flies into a searing rage, because of course deep down he will not accept being bested on the only battlefield that matters to him. He is a disgusting and violent hypocrite who has little need for nuance, and so far being this has worked out pretty great for him.

But he isn’t just a violent horrible sadist, there is a specificity to him that makes him scarier than if he was just that. He’s an intelligent, cultured and traveled man who has an extremely strong sense of justice guided by his thinking in extremely binary good-evil terms, it’s just that he’s traded his moral core with his aesthetic judgement. He’s replaced the concept of good and evil with beauty and ugliness, which is not even that far off from the way the upper class treats those to begin with. He throws parties for the wealthiest and most powerful of society, but he resents the attendants, because he finds worship of money and power to be ugly. He throws his lot with Shadaloo because they enable his tendencies and afford to let him keep living his lifestyle, but he resents everyone he works with inside of it because they are ugly and crude (and he’s frequently paired with Balrog, a guy who embodies everything he hates). He fights to save the Dolls and saves Cammy’s life, but he is disgusted by the existence of the Dolls not because of the, everything involving their creation, but because he thinks it’s a waste of beauty and is offended at the idea of turning those he deems beautiful into puppets. It is in fact pretty funny that he’s appalled at Bison for what almost consist moral grievances but really are just aesthetic ones, while Bison himself, a guy who is literally made of evil, has frequently expressed annoyance and even a little bit of disgust at Vega’s obsession, in a “I kill people too, you don’t see me being such a weirdo about it” way.

And something I find interesting about Vega, and part of why I do think they miss the mark sometimes in making him a tad too much of a sadist or pervert (like his win quotes in V about bathing in blood, when the whole reason for the claw and mask used to be that he dislikes blood and touching the opponent directly) is that he isn’t a vile murderous bastard just because, or just because of the trauma regarding his mother’s murder, but because he is a nobleman who was raised to see the world the way a nobleman does. They’ve gone back and forth over the years on whether his mom’s murder was at the hands of his birth father or stepfather, but a detail that tends to be glossed over is the fact that Vega gets his entire moral outlook from her and his environment:

• He gains his looks and personality from his mother, with the addition of corrupted feelings planted in the back of his mind during his upbringing. Vega lost sight to the meaning of life at a tender age and started to cling to his mother’s beauty, which grew into strong extremism. Those who were not deemed beautiful were not of value, and only the beautiful were worthy of survival. This is why in order to prove his strength Vega enters the arena as a prerequisite of beauty. - SF2 profile
• He was born the only child of a beautiful noblewoman from a fallen house, and an ugly but wealthy man. His twisted thoughts, obsessions and value system regarding beauty were all handed down to him by his mother. Her twisted thoughts went unrewarded, as she was murdered by her own husband. Vega was profoundly affected by this, and this trauma is said to be the reason Vega insists on maiming his opponents. - 30th Anniversary Collection

He is a guy driven by the same standards of self-improvement and excellence through combat that drive most of the other characters, except in his case, he believes that beauty is the truest form of strength, that it is the only thing that matters, that the order of the world dictates that beautiful people must never lose, and the worst thing that ever happened to him was a triumph of uglyness so world-shattering that every imperfect-looking person in the world must pay for it. Like a ninja, he is true to his code, offering second chances to fighters he deems beautiful (if only so he may savor the honor of beautifully killing them at the right time), and he is true to his high society upbringing, in that he lives to uphold and enforce a disgusting prejudiced worldview that just so conveniently puts himself at the top of everyone else, a worldview he lubricates with the blood of his opponents and a worldview that crumbles as soon as the mask comes off. He is profoundly disgusting in a way that does a lot to reinforce how evil Shadaloo is for not just enabling him but directing him, and he remains the absolute worst person inside of it no matter how much he may think of himself as above Shadaloo.

And as for him in SF6? I could honestly do without seeing any major Shadaloo players show up for 6, or even much of any of the old characters period. I wouldn’t be upset if he returned, given the wonderful job they’ve done so far on all the returning characters and new ones, I’m sure there would be room for them to do something interesting involving him and the Neo Shadaloo goobers trying to get away from the evil past of Shadaloo that Vega embodied, but I kinda don’t want to see him again unless it’s to see Chun-Li throw a couch at him again or lightning kick his face through a wall and off of a building, which is not just a high point of the series, but the most beautiful thing that ever involved Vega.